Transmission:

Transmission:

EconoShift

Type:

constant mesh

Gears:

8 forward and 2 reverse

Clutch:

dry disc

Oil capacity:

69.6 qts [65.9 L]

Four gears (1-4), plus reverse, in two ranges (L/H). Optional creeper provided a third range. Tractor must be stopped and clutch used to shift gears or range. The eight-speed transmission was only used on the 6640S.

Speeds:

With 16.9-34 rear tires.

Transmission:

Transmission:

Dual Power

Type:

two-speed power shift

Gears:

16 forward and 4 reverse

Clutch:

dry disc

Oil capacity:

69.6 qts [65.9 L]

Dual Power adds a two-speed power shift between direct drive and the lower Dual Power range to the basic eight-speed transmission. The Dual Power range is engaged by a switch on the dashboard. Dual Power was an option on the 6640S.

Speeds:

With 16.9-34 rear tires.

Transmission:

Transmission:

SynchroShift

Type:

synchronized

Gears:

12 forward and reverse

Clutch:

dry disc

Four gears (1-4) in three ranges (L/M/H) with right-hand shuttle lever. Gear shifts are synchronized. Shifts between medium and high ranges are synchronized, but the tractor should be stopped to shift to or from low range. Sychronized shuttle shifting. The 12-speed SynchroShift was standard on the 6640 SL. Dual power was an option with the SynchroShift, turning it into a 24-speed transmission.

Speeds:

With 16.9-38 rear tires.

Transmission:

Transmission:

ElectroShift/Pulse Command

Type:

four-speed power shift

Gears:

16 forward and reverse

Clutch:

wet disc

Oil capacity:

64 qts [60.6 L]

Four power shift gears arranged in two synchronized ratio groups (1-4 and 5-8). Two synchronized ranges (low/high) and right-hand shuttle. Clutch must be used to shift range or move between the lower (1-4) and higher (5-8) gear ratio groups. Push-button power shifting between the four gears in a ratio group. Push-button de-clutching on the shuttle lever allow shifting without the foot clutch. The 16 power shift was standard on the 6640 SLE.